Overheating

Okay, how do I check to see if the fan clutch is bad?

Thank you so much. I just ordered a new fan clutch and will install it soon. Thank you

So I replaced my fan clutch and it still overheated. I found that the thermostat was sticking so I replaced that as well. It worked fine for two days. Just now I drove to work and as I pulled in the drive way at work the temperature shot up again. I turned the AC off and the temperature dropped back down to normal temperature. I then parked in a parking space and turned the AC back on just to see if the temperature would shoot back up but it did not. Any suggestions on what could be wrong? The water pump is less than three months old, the fan clutch and thermostat is two days old. What should I check or do next? Thank you in advance!

It did not boil or spew over. It just showed hot on the gauge. This happened as I slowed down to go over a speed bump, at that time I turned the AC off and it returned to normal temperature. Where on the motor do I check the temperature with an IR Thermometer? How do I install a mechanical temperature gauge? Lastly, where is the sending unit on the engine? Just thinking is there anyway air in the system could cause this? I ask cause when I replaced the thermostat I lost some coolant.

So I topped off the coolant and drove the SUV for the past two days just to see what it would do. The first day it drove fine and today it did it again. I was running the AC and noticed the temperature shot up on the gauge. I turned the AC off and within a minute the temperature came back down to normal temperature. Today I noticed when the temperature was high on the gauge I lost power and as I pushed the gas it was a little shaky and lacked power until the temperature dropped back down in to normal temperature.

I plan to look and even replace the temperature sensor. But what would cause the shaky and lack of power? Does this mean it actually overheated?

Also, not sure if it matters but it also has a new radiator cap on there too?

I found this on another forum and wanted to run this by you to see if this makes sense and if you can tell me if this could also be my problem and how to test to see if this is my problem? Also, in the below passage he says "So if I run without TS, I get no overheats or spew", what does "TS" mean? And can I just bypass that so I can keep running the SUV?

And I understand the wierd overheat now:
Leaking head gasket allows compression vapor into the water jacket. Cold thermostat does not pass the vapor, (The vent in the TS is not big enough to pass all the vapor) so the block fills with vapor and pushes coolant into the (pressurized) reservoir. (So if I run without TS, I get no overheats or spew).

If there is enough coolant, it will push coolant out of the reservior, until the bubble is big enough that it starts bubbling into the bottom of the reservoir. The reservoir is connected directly to the lower radiator hose. Thermostat still closed.

Engine still warming up. Eventually, the hot vapor, or conduction, overheats the temp sender and the head overheat sensor, showing me overheat on the gauge and an alarm light. Coolant is still only warm, but spewing out reservoir, or venting vapor out reservoir.

If I turn the engine off and wait a couple minutes, the TS vent passes enough vapor to flood the jacket with coolant, and the temperature indicator instantly shows normal, and it quits spewing, although still plenty of pressure.

Finally, the TS warms up enough to open, so the bubble goes through the ts to the top of the radiator, stops spewing coolant, and the temperature remains normal.

Continued driving continues to vent vapor through the reservoir cap.

I agree and do not really know what to do at this point. I guess I should replace the temperature sensor and see what happens. Do you think that is what I should do next?

Also, should I be checking the coolant temperature sensor or the temperature sending unit or both? I know where the coolant sensor is (behind the alternator), but not sure where the temperature sending unit is located?

So I thought I knew where the sensor was, I thought it was behind the alternator besides the thermostat, but I did not see one there. Do you have any idea where it is located?